Do I need to wait?
It's confirmed.
What needed to do if it happens again?
Left click your transaction, click copy and go to
https://coinb.in/#broadcast and paste your transaction in.
If it outputs your transaction, then its rebroadcasted.
Do I nedd to upgrade electrum?
Preferably. The issue might be with the old version.
What does PM mean, I am noob...
Private Message. For example, if you want to PM shorena, you go to his profile and click "Send this user a private message". I've notified him regarding this, no worries.